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Long-Term Behavior of CFRP Strips under Sustained Loads

지속하중을 받는 탄소섬유판의 장기 거동

  • You, Young-Chan (Building Structure & Resource Research Division, Korea Institute of Construction Technology) ;
  • Choi, Ki-Sun (Building Structure & Resource Research Division, Korea Institute of Construction Technology) ;
  • Kim, Keung-Hwan (Building Structure & Resource Research Division, Korea Institute of Construction Technology)
  • 유영찬 (한국건설기술연구원 건축구조.자원연구실) ;
  • 최기선 (한국건설기술연구원 건축구조.자원연구실) ;
  • 김긍환 (한국건설기술연구원 건축구조.자원연구실)
  • Published : 2009.04.30

Abstract

Experimental study was performed to evaluate the long-term behavior of CFRP (carbon fiber reinforced polymer) strips under sustained loads including prestressing force in strengthening RC members with post-tensioned CFRP strips. Two types of CFRP strip such as unidirectional CFRP strip and hybrid CFRP strip which is composed of carbon fiber and steel plate were considered. Also two types of loading scheme were included in this study. Direct sustained loading test had been carried out to estimate the creep deformation and relaxation of CFRP strips including slip deformation at both mechanical anchorages for over 700 days. Also, flexural sustained loading test had been conducted to estimate the initial prestress losses on clamping the CFRP strips at jacking anchorages for over 90 days. From the sustained loading tests, it was observed that stress losses of unidirectional CFRP strips due to the creep deformation and relaxation of material itself and slip deformation at mechanical anchorage were ignorable. On the other hand, significant stress losses caused by the yielding of steel embedded in CFRP strips were found in case of hybrid CFRP strips due to the initial jacking force over steel yielding stress. Also, initial prestress losses during setting of CFRP strips on mechanical anchorage were about 10% of intial jacking force, which must be considered in the design.

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Cited by

  1. Combined Effects of Sustained Load and Temperature on Pull-off Strength and Creep Response between CFRP Sheet and Concrete Using Digital Image Processing vol.28, pp.5, 2016, https://doi.org/10.4334/JKCI.2016.28.5.535